Joe Marriott, Carnegie Mellon University. Advisor Scot

1
Electricity Generation Mix by US Industrial
Sectors

• Disaggregating Electricity Generation and
  Modeling Interstate Transfers
• Joe Marriott, Carnegie Mellon University
• Advisor Scott Matthews

InLCA/LCM September 2003
2
Why Disaggregate?

• Primary contributor to environmental impact is
  electricity generation
• Impacts by generation type varies a lot
• e.g. Hydro versus coal
• This variation should be reflected in LCA results
• For example Aluminum manufacturing
• Industry sector has emission numbers reduced due
  to plants in WA, which has 80 hydroelectric
  generation

3
Currently in LCA

• Use aggregate US generation mix to calculate
  emissions, GWP, etc.

Net Electricity Generation by Energy Source, 1999
4
Disaggregate Results

• Rather than a single sector
• Electric services (Utilities)
• Have multiple electricity sectors
• Electric services (Utilities, Coal)
• Electric services (Utilities, Nuclear)
• etc.
• Each industrial sector would receive a specific
  mix of these disaggregated electricity sectors

5
Making It Happen

• Data is not readily available
• Need complete facility-level transaction data for
  all US industrial sectors
• No central repository of this data
• Economic data not necessarily a good estimate
• Instead, assign a specific generation mix to each
  industrial sector using
• Locations of industry sectors from BEA
• State generation mixes from DOE

6
Sector Allocation to States

• Need percentage of each industry sector located
  in each state
• Available using a tool developed at Carnegie
  Mellon by Iavor Kostov and Scott Matthews
• Economic Census location data from BEA used for
  placement
• Then uses number of employees and shipments as
  measures of size and intensity to weight various
  sectors in various states

7
Include Interstate Trading

• Lots of electricity transfer in the United
  States, especially following deregulation in 1996
• Currently, interstate electricity transfer
  ignored, but its a big part of the market
• 30 of California power is imported
• West Virginia exports 60 of theirs
• These numbers have a significant impact, so new
  generation mixes are created for each state

8
Western US Net Imports (TWh)
3.4
14.6
2.7
-10.0
26.9
2.8
10.7
-5.6
-70.9
16.6
10.8
9
Model Linear Optimization

• Using 2 large matrices (23 x 28), find out where
  imports likely came from by minimizing distance
  (hops) traveled
• Classic transportation/distribution cost
  minimization problem
• This still isnt what is actually happening on
  the grid, but its a pretty good estimate

10
State Hops for California
3
2
3
4
1
2
4
3
4
1
2
3
0
4
1
2
3
1
11
Complete US Hop Count
12
Complete US Hop Count
13
Completed Optimization, Showing Electricity
Transactions in TWh
14
Generating the Generation Mix

• Have the of imports for each importing state
• Example CA imports 30
• Have the of that imported amount that came from
  each exporter
• AZ 34, MT 3, NM 19, UT 4, WA 36
• Know the mix of the amount from each importer
• Arizona 45 Coal, 10 Gas, 35 Nuclear, 10
  Hydro
• Multiply these 3 sets of percentages, normalize
  with existing generation mix to get the new values

15
The Next Generation (Mix) in CA
16
Electricity Allocation to Sectors

• Now, apply each states generation mix to the
  percentage of all the industrial sectors in the
  state
• 20 of all widgets are manufactured in CA, so 1/5
  of the widget sector will have CAs generation
  mix
• Then sum the generation types across all sectors
  and states
• Each sector now includes part of the generation
  mix for each state its located in

17
Results of Modification
Industries with the highest specific electricity
generation mix values (by energy source) in the
U.S. economy
18
Aircraft Manufacturing
19
Dirty Laundry? And How!
20
United States Well Oiled
21
Results Trend Towards Average
22
Contributions

• Disaggregating adds accuracy to a critical sector
  in terms of environmental impact
• Industrial sector generation mixes answer some
  interesting questions
• Which sectors are vulnerable to shifts in fuel
  price or technology change?
• What is the potential impact of carbon taxes on
  the US economy?
• Import-export estimate an intuitive substitute
  for complete transmission grid analysis
• Most industrial sectors have a mix close to the
  US average mix
• Some interesting sectors have significant
  differences